title: Holographic particle-streak velocimetry.
abstract: We present a way to measure the positions and instantaneous velocities of micrometer-scale colloidal spheres using a single holographic snapshot obtained through in-line holographic video microscopy. This method builds on previous quantitative analyses of colloidal holograms by accounting for blurring that occurs as a sphere moves during the camera's exposure time. The angular variance of a blurred hologram's radial intensity profile yields both the magnitude and direction of a sphere's in-plane velocity. At sufficiently low speeds, the same hologram also can be used to characterize other properties, such as the sphere's radius and refractive index.
authors.affiliation: Department of Physics and Center for Soft Matter Research, New York University, New York, NY 10003, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Dixon
authors.forename: Fook Chiong
authors.initials: FC
authors.lastname: Cheong
authors.forename: David G
authors.initials: DG
authors.lastname: Grier
mesh_terms: D000465:Algorithms; D006696:Holography / Q000379:methods*; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018715:Microscopy, Video / Q000379:methods*; D008863:Microspheres; D015203:Reproducibility of Results; D012212:Rheology / Q000379:methods*; D012680:Sensitivity and Specificity